In context, yes. Depending on where it is spewing, it could be. Most places, no.
To totally ignore context is to look foolish.
What about nitrogen fertilizer? It helps plant growth, so dumping it MUST be good...it CAN'T be a pollutant by the claims here. Yet, if you put more onto the soil than the system can handle, it can mean contaminated groundwater or surfacewater that can cause death or eutrophy lakes excessively.
Where is water vapor coming from a smokestack a pollutant? Where is carbon dioxide coming from a smokestack a pollutant?